Tubular heat exchange systems are used throughout different industries and examples of which are condensers of turbines, refrigeration units, heat exchangers in gas cooling systems and scrubbing systems. They are also used in power plants, desalination modules and petrochemical industries. These tubular heat exchange systems typically use a fluid circulating through several tubes bundled together for the heat exchange. The operations of such heat exchange systems are well-known in the art and will not be discussed in detail.
Invariably, maintenance of these tubes is necessary for efficient heat exchange. Debris and fouling deposits as a result of precipitation, corrosion, crystallization and chemical reactions within the tubular heat exchange systems can clog up the tubes. Traditional methods of cleaning these tubes require the shutting down of the heat exchange system, taking it off-line and physically flushing the individual tubes.
New cleaning systems have been developed using elastomeric balls in the fluid circulating in the tubes of the heat exchange system. A number of balls circulating in the heat exchange system will result in the balls passing through at least a certain number of the tubes. As the balls pass through the tubes, any fouling deposits or debris in the tubes are often pushed out. This new cleaning method has proven to be relatively effective in reducing the frequency of shutting down the heat exchange system for maintenance. Such systems have become well-known and an example of which is disclosed in U.S. Pat. No. 5,592,990.
In such tube cleaning systems using circulating balls, a means for separating the balls from the heat exchange system is essential. The elastomeric balls are worn out after a certain period of time and the cleaning efficiency may be decreased as the balls are too small to effectively remove fouling deposits from the tubes. The worn-out balls need to be collected and separated from the heat exchange system so that new balls may be introduced. In U.S. Pat. No. 5,592,990, a ball collector housing is used to collect the balls and separate them from the fluid, omitting a separate reservoir for introducing balls into the system. However, it is an all-or-nothing approach as even balls that are not worn-out are also collected and disposed of.
In U.S. Pat. No. 4,974,662, a ball separator is used to classify the balls according to different predetermined sizes by using openings bounded by crests of parallel rails. The separated worn-out balls are then collected in a basket for removal. While only the worn-out balls are separated from the fluid, use of a drive pump is required to provide sufficient pressure such that the balls can be forced through the ball separator.
At present, there is still a lack of a non-powered cleaning system using balls for cleaning tubes in heat exchange system with an efficient and effective means for separating worn-out balls from the fluid.